Web slitting and rewind machine



Oct. 31, 1967 S, E, AMOS 3,350,026

' WEB SLITTING AND REWIND MACHINE Filed March 15, 1966 ATTORNEY United States Patent 3,350,026 WEB SLITTING AND REWIND MACHINE Stephen Earl Amos, Circleville, Ohio, assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Mar. 15, 1966, Ser. No. 534,389 2 Claims. (Cl. 242-563) This invention relates to web-winding machines and more particularly to improved web-slitting and rewinding machines.

A principal object of this invention is to provide improved web-winding machinery operative to rewind slit rolls of uniform quality despite wide variations in gauge across the web to be slit and rewound. The foregoing and additional objects will more clearly appear in the detailed description to follow.

These objects are fully realized in the present invention which, briefly stated, comprises in a continuous web slitting and rewind machine, the combination of a driven transport roller mounted for rotation on a fixed horizontal axis, means for driving said. roller, an unwind mandrel adapted to support a web supply (i.e. mill) roll, the axis of said mandrel being parallel to the axis of saidroller and mounted for straight line movement toward and away from said roller, means for constantly urging said mandrel toward said roller whereby the web supply roll supported thereon is maintained in contact with said roller, means for retarding the rotation of said mandrel, at least one driven rewind mandrel adapted to support a plurality of rolls of slit web, the axis of said rewind mandrel being parallel to the axis'of said roller and mounted for straight line movement toward and away from said roller, means for constantly urging said rewind mandrel toward said roller, means for driving said rewind mandrel at constant torque, and a plurality of slit roll cores mounted in spaced relationship on said mandrel, and a resilient bushing between each core and the windup mandrel in frictional driving contact with said core and said mandrel.

An understanding of my invention will be facilitated by reference to the accompanying drawing wherein:

FIG. 1 is a schematic representation, in perspective, of a prefer-red embodiment of my invention employing a plurality of rewind mandrels;

FIG. 2 is a schematic view illustrating the resilient sleeves disposed in spaced relationship on the rewind mandrel;

FIG. 3 is a view partially in section which illustrates a retarding means with parts as disposed at the beginning of the slitting operation;

FIG. 3A is a view partially in section which illustrates the disposition of the parts of the retarding means of FIG. 3 near the end of the slitting operation; and

FIG. 4 is a schematic perspective view of an alternative embodiment of the apparatus of the present invention.

Referring to FIG. 1, the relationship of the various elements can be seen. Driven transport roller 10, driven by motor 11, frictionally engages supply roll 12 which contains the web to be slit. Roller rotates in the clockwise direction, thus the web unwinds from roll 12 onto the upper side of the roller 10, as shown. Roll 12 is mounted on mandrel 13 which in turn is moveably mounted on straight line guide ways 14 and 14 and is urged by pneumatic means 16 and 16' to maintain supply roll 12 in frictional engagement with roller 10. Rotation retarding means is provided in order to maintain tension on the web; in the preferred embodiment mandrel 13 is extended and fitted with a disc brake, having disc 18 which engages brake shoe 19 on a fixed mount 20 so that as the radius of the supply roll decreases with the unwinding 3,350,026 Patented Oct. 31, 1967 of the web, the disc moves inward toward roller 10 and decreases the radius arm of the disc brake (FIGS. 3 and 3A.). The braking force is thus proportional to the torque applied to the supply roll as it is driven by surface contact with roller 10, facilitating the maintenance of constant tension. While the means to urge the supply roll is illustrated as a pneumatic cylinder, which is coupled to a source of compressed air, which optionally may be equipped with conventional adjustable diaphragm valve (not shown), it is understood that springs or other pressure means may be employed.

Referring again to FIG. 1, in the preferred embodiment, the web receiving means comprises tandem windup mandrels 22 and 22'. These are respectively moveably mounted with bearings 23, 23' and 23" respectively, in guide track 25, 25 and 25" respectively, with pneumatic means 27, 27' and 27" respectively (optionally these may be springs on other than pneumatic cylinders), to urge slit web windup rolls 31, 31', 31", etc., on mandrel 22 and similar rolls 32, 32', 32", etc., on mandrel 22' into frictional engagement with transport roller 10. Each windup mandrel is driven by a motor 34, which is preferably a torque motor so as to provide constant torque independent of speed to assist surface drive of windup rolls. A plurality of slitting knives 30 supported across transport roller 10 are positioned so that the knives engages the web and slit it into narrow widths. These are wound on spaced apart rolls 31, 31, 31", etc., and 32, 32', 32", etc., on mandrels 22 and 22, respectively. Transport roller 10 preferably has a plurality of circumferential grooves into which the slitting knives fit, the groove is found to increase the useful life of the cutting edge of the knives over the life of the edges of the knives that ride on the solid surface of the roller as they cut through the web.

FIG. 2 illustrates two essential features of the present invention: resilient (e.g. sponge rubber) bushing intermediate the windup roll cores and the mandrel and in frictional driving contact with both the core and mandrel, and spacers between the windup rolls permitting some independence of rotation to allow slightly different angular velocities by virtue of winding rolls of slit web in which slight variations in gauge cumulatively can result in dif ferences in circumference among various rolls. Shown in the figure is a portion of mandrel 22. Rolls 31, 31', 31", 31", etc., are positioned on this mandrel with spacers 35, 35, 35" between rolls. These spacers prevent lateral contact between rolls to permit independent rotation. Each roll is wound on a core 36, 36', 36", 36', etc., and between each core and the mandrel is a resilient bushing 37, 37, 37", 37", etc., to allow slight radial movement of the roll in response to variations in diameter caused by gauge differences. Due to the force exerted by urging means 27 of FIG. 1 (and the corresponding elements of a second mandrel), resilient bushings 37, 37', 37", 37", etc., are distorted so that the periphery of each slit roll i held in frictional contact or engagement with roller 10, thus uniform contact of the periphery of each slit roll with the transport roller is maintained. The bushings are of a resilient sponge rubber, sufficient to permit a radial distortion of approximately i5% of the diameter of a finished roll (eg 10 inches) under a pressure of 5 psi. As shown in FIG. 2, the spacers may also comprise a resilient bushing; conveniently one may employ, as the spacers, empty cores and their associated resilient bushings.

The action of the disc brake is illustrated in FIGS. 3 and 3A. Shown in the figures is supply roll 12 engaging driven transport roller 10 with mandrel shaft 13 extended, and having mounted thereon disc 18 having a diameter substantially the sameas the initial diameter of the supply roll, which frictionally engages brake shoe 19 mounted on support 20. In FIG. 3, supply roll 12 has 3 radius R,- with braking radius R FIG. 3A shows substantially expended supply roll 12, with radius R and braking radius R This braking apparatus, thus provides uniform reduction of the braking force as the supply roll is expended:

a m Rb Ry The brake disc and the supply roll core are fixed to the shaft so that they rotate togther. The disc may be of any suitable metal, e.g., steel, aluminum, aluminum alloy, brass and the like; the brake shoe is of a fibrous nonmetallic material commonly used for brakes, such as compositions containing asbestos.

The surface of transport roller is preferably covered with rubber, of a moderate density, e.g. a 30-40 Shore A, finished to a fine pebbly surface. The thickness should be sufiicient to accommodate slits by the slitting knives, which are allowed to cut through the coating on their initial contact. The grooves may be as close together as inch and still provide good support for the web during slitting, so the coating need not be replaced after each use.

Referring to FIG. 2, windup rolls are spaced apart by cylindrical spacers 35, 35', 35", 35", etc.; these may be of nylon or other plastic material to allow freedom of rotation of separate rolls, or as stated above they may be made up of the cylindrical slit roll core material and the resilient bushing. It is important, however, to have the width of the spacer precisely the same as the desired spacing, such as the width of the adjacent slit width of web wound on the second tandem mandrel.

FIG. 4 illustrates the present invention adapted to the vacuum withdrawing system of US. Patent 3,144,216. Shown in this figure are basically the same elements of FIG. 1, but instead of tandem windup mandrels a single mandrel is employed, with dual slitting knives which slit a very narrow width of web which is withdrawn by vacuum ducts 41 and 42. This arrangement is particularly useful for slitting a wider web into two or more wide widths, and for slitting capacitor film from metallized film having an unmetallized margin on the capacitor film.

What is claimed is:

1. In a continuous web slitting and rewind machine, the combination of a transport roller mounted for rotation on a fixed horizontal axis, means for driving said roller, and unwind mandrel adapted to support a web supply roll the axis of said mandrel being parallel to the axis of said roller and mounted for straight line movement toward and away from said roller, means for constantly urging said mandrel toward said roller whereby the web supply roll is maintained in contact with said roller, means for retarding the rotation of said mandrel, at least one driven rewind mandrel adapted to support a plurality of rolls of slit web on cylindrical cores, the axis of said rewind mandrel being parallel to the axis of said roller and mounted for straight line movement toward and away from said roller, means for constantly urging said rewind mandrel toward said roller, means for driving said rewind mandrel at constant torque, a plurality of cylindrical slit roll cores mounted in spaced relationship on said rewind mandrel, and a resilient bushing between each core and the rewind mandrel in frictional driving contact with the core and the rewind mandrel.

2. The machine of claim 1 wherein the means for retarding the rotation of said mandrel comprises a disc mounted at one end of said mandrel for rotation therewith, and a stationary brake shoe in contact with the face of said disc.

References Cited UNITED STATES PATENTS 2,984,427 5/1961 Rockstrom 242- 2,985,398 5/1961 Rockstrom et al 242-65 3,144,216 8/1964 Billingsley 242-56.4

LEONARD D. CHRISTIAN, Primary Examiner. 

1. IN A CONTINUOUS WEB SLITTING AND REWIND MACHINE, THE COMBINATION OF A TRANSPORT ROLLER MOUNTED FOR ROTATION ON A FIXED HORIZONTAL AXIS, MEANS FOR DRIVING SAID ROLLER, AND UNWIND MANDREL ADAPTED TO SUPPORT A WEB SUPPLY ROLL THE AXIS OF SAID MANDREL BEING PARALLEL TO THE AXIS OF SAID ROLLER AND MOUNTED FOR STRAIGHT LINE MOVEMENT TOWARD AND AWAY FROM SAID ROLLER, MEANS FOR CONSTANTALY URGING SAID MANDREL TOWARD SAID ROLLER WHEREBY THE WEB SUPPLY ROLL IS MAINTAINED IN CONTACT WITH SAID ROLLER, MEANS FOR RETARDING THE ROTATION OF SAID MANDREL, AT LEAST ONE DRIVE REWIND MANDREL ADAPTED TO SUPPORT A PLURALITY OF ROLLS OF SLIT WEB ON CYLINDRICAL CORES, THE AXIS OF SAID REWIND MANDREL BEING PARALLEL TO THE AXIS OF SAID ROLLER AND MOUNTED FOR STRAIGHT LINE MOVEMENT TOWARD AND AWAY FROM SAID ROLLER, MEANS FOR CONSTANTLY URGING SAID REWIND MANDREL TOWARD SAID ROLLER, MEANS FOR DRIVING SAID REWIND MANDREL AT CONSTANT TORQUE, A PLURALITY OF CYLINDRICAL SLIT ROLL CORES MOUNTED IN SPACED RELATIONSHIP ON SAID REWIND MANDREL, AND A RESILIENT BUSHING BETWEEN EACH CORE AND THE REWIND MANDREL IN FRICTIONAL DRIVING CONTACT WITH THE CORE AND THE REWIND MANDREL. 